1. Field of the Invention
This invention relates to hydraulic lash adjusters as used in the valve trains of internal combustion engines or similar mechanisms and more particularly to hydraulic lash adjusters of the self-contained type in which the fluid is sealed within the assembly with no provision for its replacement from any external source during operation.
2. Prior Art
The conventional lash adjuster of this type comprises a cylindrical body with a blind bore and a plunger slidably mounted in the blind bore. When the plunger is moved in the axial direction by the force applied thereto through a transmitting member such as a fulcrum in engagement therewith, the plunger is simultaneously urged to move in the radial direction of the body and the outer surface of the plunger is brought into contact with the inner surface of the body by a component of the force since the direction of the force does not correspond to the axis of the plunger. Between the inner surface of the body and the outer surface of the plunger, there is provided a leakage clearance through which a very small amount of silicone oil passes. Since the silicone oil has little or no lubricating effect, the inner surface of the body and the outer surface of the plunger will be subjected to frictional wear thereby decreasing the accuracy of the lash adjuster in operation.